Isibonelo Colliery is situated in the Mpumalanga Province between the towns of Kinross, Secunda, Bethal and Kriel near the northern margin of the Highveld coalfield of Mpumalanga. The Isibonelo Colliery mine lease area is located on the following properties.
1. Alexander 12 IS;
2. Witbank 102 IS;
3. Boschmanskraal 113 IS;
4. Brakfontein 117 IS;
5. Aangewys 81 IS;
6. Onverwacht 70 IS;
7. Vlaklaagte 83 IS;
8. Rietfontein 100 IS; and
9. Rietfontein 101 IS.

Bituminous coal seams hosted by the sedimentary strata in the Isibonelo Colliery Mining Licence area include, from the base up, the No 1, 2, 3, 4 and 5 seams. Only the No 4 seam is presently considered to be economically viable, with an average opencast depth of 40m and a thickness of 5,6m.

Isibonelo Colliery primarily utilizes the dragline strip-mining method as a means of coal removal from the coal seams encompassed in the Highveld coalfield and the truck and shovel method.

Isibonelo Colliery currently operates three open cast pits, namely the North Pit, Central Pit and South Pit.

Coal is exposed by removing the overburden via dragline or truck and shovel operations; prior to removing the overburden, the topsoil is stripped and stored separately for re-use later during rehabilitation of the pit(s).

The dragline (a large scale digging machine) is used by Isibonelo Colliery to remove hard overburden through bench striping, while truck and shovel techniques are used to remove softer overburden materials. One dragline mines on either side of the ramp in the South Pit, and the second dragline mines the North and Central Pits. The Central Pit is typically mined from South to North while the north and south pit typically follow a southerly mining direction (away from the Steenkoolspruit).

A 'chop' limit of 15m and a maximum dig depth of 42m is applied for the draglines, along with double benching in order to maximise draglines utilisation duaring stripping, over and above the more expensive truck and shovel techniques, during the removal of hard overburden materials. Isibonelo Colliery typically follows two approaches during stripping and benching, namely:

Method 1: Is a single bench operation where all soft overburden is stripped by truck and shovel equipment and the hard overburden is bench stripped by the dragline. Some hard overburden can also be stripped in the isolated deep overburden blocks.

Method 2: Is a double bench operation applied in the deep portions (where the dragline hard overburden bench exceeds the 42m depth/dig limit for the Marion 8200) of the pit.

Soil Handling
Overburden comprises the surface materials overlaying the mineral deposit / coal that require removal, while inter-burden refers to the materials located between mineral deposits. Spoils refers to the excavated materials (i.e. removed overburden) that will be used during rehabilitation.

Topsoil Berms.
Prior to the commencement of the open cast/pit operations at Isibonelo Colliery, a berm was constructed along the Steenkoolspruit for the purpose of flood management. The berm was constructed from wetland soils stripped to a depth of 500mm from the spoils laydown area. The berm is approximately 3m high with an average slope of 1:5 on the Steenkoolspruit side, with the foot slope approximately 1:7 rising to a crest slope of 1:3.

During the initial mining operations, spoils/overburden removed from the open cast/pit were placed between this berm and the edge of the open cast / pit, ensuring that it does not encroach over the top of the berm into the river. No carbonaceous or potentially polluting material was used for berm construction and the berm has subsequently been re-vegetated to prevent erosion.

Drilling and Blasting.
Following from the above stripping, the exposed coal is drilled and blasted, before being placed into haul trucks for transportation to the crushed plant.

In some instances, the drilling and blasting of hard overburden materials is required. In these, instances, the drilling and blasting of hard overburden and inter-burden (material occurring in-between ore bodies, in this case between coal) occurs in advance of the dragline.

Overburden and Inter-burden Blasting.
All overburden and inter-burden blasting is sequential, meaning the initiation of a blast within a single hole is delayed until the hole before has already been initiated and blasted i.e. during a blast event only a single hole will fire at a time.

The blast hole diameters do not exceed 271mm and the charge mass per hole does not exceed 1200kg. If the proposed holes are so deep that the charge mass will exceed 1200kg then the charge density or the hole diameter will be reduced to limit the charge mass per hole to 1200kg.

Coal blasting.
Hole diameters for coal blasting do not exceed 127mm. In areas where 20 hole diameters of stemming cannot be applied because the holes are too short, hole diameters are reduced accordingly.

Conveyor.
Coal is hauled from the pits to a central crushing plant and transported via an overland conveyor to a common 8 000 ton open longitudinal surge bunker and emergency stockpile. Coal is loaded from this bunker onto another conveyor and transported to the central coal stockpile at the SSF Secunda Complex. The conveyor belt runs at a speed of 4.2m/s over a distance of 12km and is covered with suitably covered by metal sheeting.

Belt turnovers are utilised to minimise spillage along the trajectory of the conveyors. Dust mitigation is performed via water spraying at the transfer points which are located within the strip mine area and at the Syferfontein coal handling area. Wash down water at the transfer points is collected and transferred to evaporation and settling dams where the coal is recovered and fed back into the system.

Access to the Isibonelo Colliery offices is via the N17 and R547, with the opencast operation accessed via the internal Isibonelo Colliery access road, previously the dragline walkway, which was constructed adjacent to the Sasol overland conveyor belt.

Isibonelo Colliery electricity is supplied from Syferfontein Colliery via power supply cables installed along the conveyor route, at a tension of 132kV and 22kV. The 132kV supply is a dual feed system on common suspension structures. Power is supplied to the strip mine areas via substations at a rate of 45MVA 20MVA. The 22kV power supply is a permanent line which supplies the necessary power required to walk the dragline to a new strip mine site and is also used as a ring-feed.

The extracted coal is delivered to the primary in-pit sizing plant prior to placement on the overland conveyor and relocation to the IC surge bunker and emergency stockpile area located near IC’s offices and SSF conveyor system. The coal in the said bunker is then handed over to Sasol and transported to the SSF Secunda Complex via Sasol’s overland conveyor.

The crusher plant is located 5 - 8m below ground-level with the overland conveyor exiting to ground-level at a 16 degree angle. The tipping ramp is about 15m above ground level with an additional 1 - 2m housing on top of this concrete structure. The tipping bay is enclosed by the steel housing and a security fence and lighting was installed around the plant.